• International Journal of Aeronautical and Space Sciences
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• 제5권2호
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• pp.43-53
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• 2004

Collision avoidance for multiple aircraft can be stated as a problem ofmaintaining safe distance between aircraft in conflict. Optimal collision avoidanceproblem seeks to minimize the given cost function while simultaneously satisfyingconstraints. The cost function could be a function of time or control input. This paper addresses the trajectory time-optimization problem for collision avoidance of unmanned aerial vehicles(UAVs). The problem is difficult to handle in general due to the two-point boundary value problem subject to dynamic environments. Some simplifying aleorithms are used for potential applications in on-line operation.Although under possibility of more complicated problems, a dynamic problem is transformed into a static one by prediction of the conflict time and some appropriate assumptions.

• Journal of Korean Society of Industrial and Systems Engineering
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• 제29권1호
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• pp.63-71
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• 2006

In this paper, we consider a planning problem arising from printed circuit board manufacturing industries. Given a set of several types of PCBs, component feeders and surface mounting machines in series in a PCB assembly line, the problem is to define the feeder allocation and job sequence with the objective of minimizing the total operation time of the line. We formulate the problem as a mathematical model. And, the problem is proven to be NP-hard, so a genetic algorithm is developed. Finally, we give test results to evaluate the performance of the genetic algorithm.

• Journal of Oriental Neuropsychiatry
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• 제28권2호
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• pp.61-72
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• 2017

Objectives: The Yin-Yang temperament and the Sasang Personality Questionnaire (SPQ) were reported to have relations with psychopathological problems in adolescents. The purpose of this study was to examine how domains of Yin-Yang temperament influence on problem behaviors in Korean middle school students. Methods: Subjects of 681 Korean middle school students completed the SPQ for measuring Yin-Yang temperament and the Youth Self-Report (YSR) for measuring problem behaviors. The differences of problem behaviors between Yin and Yang temperament groups were tested with T-test and profile analysis. The associations of the SPQ subscales on problem behaviors was also examined with Pearson's correlation and regression analysis. Results: Yang temperament was related to the externalizing problem while Yin temperament to the internalizing problem. The Emotionality and Behavior dimension of Yin-Yang temperament were found to be a factor of susceptibility and resilience for problem behaviors, respectively. Three dimensions of Yin-Yang temperament have different influences on externalizing and internalizing problems depending on the sex and Yin-Yang temperament groups of subjects. Conclusions: The Yin-Yang temperament would be useful for predicting and preventing the problem behaviors of middle school students. This study would be useful for screening the psychopathological problems and helping Korean adolescents to develop healthy character.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2003년도 The Fifth Asian Computational Fluid Dynamics Conference
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• pp.13-14
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• 2003

Two different ${\kappa}-{\varepsilon}-\overline{{\nu}{\nu}}-f$ turbulence models together with the two-layer model are evaluated for natural convection in a rectangular cavity. The numerical problem and accuracy of the turbulence models are discussed. The original $\overline{{\nu}{\nu}}-f$ model suffers from the numerical stiffness problem when used with the segregate solution procedure like the SIMPLE algorithm, and a remedy for this problem is proposed. It is shown that original $\overline{{\nu}{\nu}}-f$ model best predicts the mean velocity, Reynolds stresses and the turbulent heat flux while the modified $\overline{{\nu}{\nu}}-f$ model (N=6) overpredicts the turbulent quantities.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 한국해양정보통신학회 2008년도 추계종합학술대회 B
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• pp.783-786
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• 2008

외판원문제(Traveling Salesman problem: TSP)는 전형적인 조합최적화 문제로 위치하는 n개의 모든 지점을 오직 한번씩만 방문하는 순회경로를 결정하는 과정에서 순회비용 또는 순회거리를 최소화한다. 따라서 본 논문에서는 종래의 NP-hard문제로 널리 알려진 TSP를 해결하기 위해서 메타 휴리스틱기법 중에서 가장 널리 이용되고 있는 유전 알고리즘(Genetic Algorithm: GA)을 이용한다. 마지막으로, 유전 알고리즘을 이용해 외판원문제에 적합한 성능을 보이는 유전 연산자를 찾아내기 위해 수치 실험을 통해 그 성능에 대한 평가를 한다.

• International Journal of Control, Automation, and Systems
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• 제2권4호
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• pp.475-484
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• 2004

In this paper, we present a dynamic output-feedback receding horizon $H_{\infty}$controller for linear discrete-time systems with disturbance. The controller is obtained numerically from the finite horizon output-feedback $H_{\infty}$optimization problem, which is, in fact, hardly solved analytically. Under a matrix inequality condition on the terminal weighting matrix, the monotonic decreasing property of the cost is shown. This property guarantees both the closed-loop stability and the $H_{\infty}$norm bound. Then, we extend the proposed design method to a reference tracking problem and a problem for time-varying systems. Numerical examples are given to illustrate the performance of the proposed controller.

• Journal of the Korean Operations Research and Management Science Society
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• 제26권3호
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• pp.95-104
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• 2001

In this paper, we consider a maximin version of the linear programming knapsack problem with extended generalized upper bound (GUB) constraints. We solve the problem efficiently by exploiting its special structure without transforming it into a standard linear programming problem. We present an O(n$^3$) algorithm for deriving the optimal solution where n is the total number of problem variables. We illustrate a numerical example.

• Proceedings of KOSOMES biannual meeting
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• 해양환경안전학회 2004년도 추계학술발표회
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• pp.63-68
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• 2004

In this paper, we will introduce the predominant rose on the marine leisure business of the overseas. Next we will analyze the current situation of the domestic marine leisure and draw up a plan to solve its problem

• Journal of the Korea Convergence Society
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• 제10권9호
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• pp.265-272
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• 2019

In this study, 'poverty', which we think in our daily life, started from something. In particular, this study typified the perception of poverty by using the 'Q methodology', a subjective research method, to examine individual subjective opinions. The results of the analysis are as follows. is a "Retraction type", and poverty is a problem of 'Retention', 'Individual Effort Problem', 'Social Structure Problem', 'Low Status' and 'Laziness'. is a "Individual Problem type", and emphasizes 'Individual Effort Problem', 'Laziness', 'Incompetence', 'Starvation' and so on. is a "Basic Problem type", and emphasizes the basic element of life such as 'The Food and Shelter problem', 'Starvation', 'Laziness', and 'No Money'. is a "Resource Distribution Problem Type" that emphasizes the problem of resource allocation according to social structural problems. This study typifies the perception of poverty using subjectivity research method on 21st century and expects converging extension study to empirical studies for generalization.

• Journal of the Korean Operations Research and Management Science Society
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• 제17권1호
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• pp.41-41
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• 1992

In the real world situations that some jobs need be processed only on certain limited machines frequently occur due to the capacity restrictions of machines such as tools fixtures or material handling equipment. In this paper we consider n-job non-preemptive and m parallel machines scheduling problem having two machines group. The objective function is to minimize the sum of earliness and tardiness with different release times and due dates. The problem is formulated as a mixed integer programming problem. The problem is proved to be Np-complete. Thus a heuristic is developed to solve this problem. To illustrate its suitability and efficiency a proposed heuristic is compared with a genetic algorithm and tabu search for a large number of randomly generated test problems in ship engine assembly shop. Through the experimental results it is showed that the proposed algorithm yields good solutions efficiently.